Starship Asterisk*

Joe Walker wrote: ↑Wed Sep 09, 2020 6:37 pm I'm trying to understand how the stars in the star cluster move up and down (or in a circle like an orbit around a point in space) as they are riding the gravitational waves. I estimate that they could be moving about 20,000,000 miles from peak to trough (or front to back) and at a frequency of 2,000 Hz (from the LIGO recording). Since they are gaseous wouldn't they just be smeared/obliterated? Or do gravitational waves move tremendous masses at near the speed of light and do no harm to the geometry of the masses? Thanks for any info.

LeighGus wrote: ↑Wed Sep 09, 2020 2:03 pm
If a human were close enough to a black hole merger event, say within a light year or closer, would the human eye perceive spacial distortions from the gravity waves?

... if one was looking at the black holes through a telescope from close range, what would one see? What if one turned the telescope 180° away to look at stars in the local distance, what would we see?

LeighGus wrote: ↑Wed Sep 09, 2020 2:27 pm

orin stepanek wrote: ↑Tue Sep 08, 2020 12:19 pm GW190521_Virgo_1080.jpg


Oh My!!! Kaboom! 🌪 If 2 black holes collide; would not that be like 2 strong magnets coming together???? Either banging together or sling themselves fast apart?

It seems to me that the comparison is not the same. The two magnets are directly approaching each other and are pulled directly in by the mutual attraction. The two black holes are orbiting each other. The orbits are just unstable enough that they spiral in toward each other and eventually scrape each other and merge. There is insufficient lateral energy for a slingshot to happen.

I do believe that slingshots can and do happen if the two black holes are not captured by each other into orbits. I wonder what the minimum parameters for a slingshot would be. I suppose it depends on their masses, relative velocities, angles of approach, and so on.

LeighGus wrote: ↑Wed Sep 09, 2020 2:27 pm

orin stepanek wrote: ↑Tue Sep 08, 2020 12:19 pm GW190521_Virgo_1080.jpg


Oh My!!! Kaboom! 🌪 If 2 black holes collide; would not that be like 2 strong magnets coming together???? Either banging together or sling themselves fast apart?

It seems to me that the comparison is not the same. The two magnets are directly approaching each other and are pulled directly in by the mutual attraction. The two black holes are orbiting each other. The orbits are just unstable enough that they spiral in toward each other and eventually scrape each other and merge. There is insufficient lateral energy for a slingshot to happen.

I do believe that slingshots can and do happen if the two black holes are not captured by each other into orbits. I wonder what the minimum parameters for a slingshot would be. I suppose it depends on their masses, relative velocities, angles of approach, and so on.

LeighGus wrote: ↑Wed Sep 09, 2020 2:27 pm

orin stepanek wrote: ↑Tue Sep 08, 2020 12:19 pm GW190521_Virgo_1080.jpg


Oh My!!! Kaboom! 🌪 If 2 black holes collide; would not that be like 2 strong magnets coming together???? Either banging together or sling themselves fast apart? ⁉️ 🤯

It seems to me that the comparison is not the same. The two magnets are directly approaching each other and are pulled directly in by the mutual attraction. The two black holes are orbiting each other. The orbits are just unstable enough that they spiral in toward each other and eventually scrape each other and merge. There is insufficient lateral energy for a slingshot to happen.

I do believe that slingshots can and do happen if the two black holes are not captured by each other into orbits. I wonder what the minimum parameters for a slingshot would be. I suppose it depends on their masses, relative velocities, angles of approach, and so on.

orin stepanek wrote: ↑Tue Sep 08, 2020 12:19 pm GW190521_Virgo_1080.jpg


Oh My!!! Kaboom! 🌪 If 2 black holes collide; would not that be like 2 strong magnets coming together???? Either banging together or sling themselves fast apart?

Ann wrote: ↑Wed Sep 09, 2020 5:00 am

orin stepanek wrote: ↑Wed Sep 09, 2020 12:41 am I got another dum dum for ya all! every planet seems to have 2 polls; doesn't a black hole? That's why I asked the first dum dum in the first place! I think art tried to answer that; but I'm not as smart as I used to be! You start getting brain farts when you get my age!

Hey, Orin, Bruce just answered your question about whether rotating black holes have two poles (they do), but I can't help noticing the expression you used, "brain farts"! (Yes, don't I know the feeling.)

My point is, though, that I spend way too much time on Youtube, and since I try to stimulate my brain cells a little by not just watching cute kittens, I watch some videos on history, too. There is a nice series calling Tasting History, which discusses what people ate at different times and in different places, and then cook their dishes for us, too.

Well, the latest episode I saw was called "Farts of Portingale", can you believe it? These "farts" were popular during Shakespeare's time, and people might have eaten some as they took a break from a performance of Hamlet or Othello! (The audience might have eaten them, I mean, the actors may have stayed on stage instead of having a snack.) The "farts" were basically little meat balls with dates and raisins.

Perhaps better to eat your farts than to have them on your brain!

Ann

orin stepanek wrote: ↑Wed Sep 09, 2020 12:41 am I got another dum dum for ya all! every planet seems to have 2 polls; doesn't a black hole? That's why I asked the first dum dum in the first place! I think art tried to answer that; but I'm not as smart as I used to be! You start getting brain farts when you get my age!

orin stepanek wrote: ↑Wed Sep 09, 2020 12:41 am I got another dum dum for ya all! every planet seems to have 2 polls; doesn't a black hole? That's why I asked the first dum dum in the first place! I think art tried to answer that; but I'm not as smart as I used to be! You start getting brain farts when you get my age!

johnnydeep wrote: ↑Tue Sep 08, 2020 6:32 pm

Chris Peterson wrote: ↑Tue Sep 08, 2020 6:24 pm

johnnydeep wrote: ↑Tue Sep 08, 2020 6:12 pm

Hmm, I hadn't realized that a black hole could have a charge. And doesn't it also follow that any such charge must be small, because if it was large, the black hole would be blown apart by electrostatic repulsion, since that force is 10⁴⁰ times greater than gravity?

How do you blow a singularity apart? It has no volume.

True. Well, maybe I was thinking it could never form in the first place if the infalling matter had too much net charge. Like, it would be pretty hard to form a BH solely out of, say, protons. But I guess that wouldn't stop an already existing BH to eat a stream of protons and keep the charge.

wikipedia/black hole wrote:The no-hair conjecture postulates that, once it achieves a stable condition after formation, a black hole has only three independent physical properties: mass, charge, and angular momentum; the black hole is otherwise featureless. If the conjecture is true, any two black holes that share the same values for these properties, or parameters, are indistinguishable from one another. The degree to which the conjecture is true for real black holes under the laws of modern physics, is currently an unsolved problem.[51]

These properties are special because they are visible from outside a black hole. For example, a charged black hole repels other like charges just like any other charged object. Similarly, the total mass inside a sphere containing a black hole can be found by using the gravitational analog of Gauss's law (through the ADM mass), far away from the black hole.[62] Likewise, the angular momentum (or spin) can be measured from far away using frame dragging by the gravitomagnetic field, through for example the Lense-Thirring effect.[63]

Chris Peterson wrote: ↑Tue Sep 08, 2020 6:24 pm

johnnydeep wrote: ↑Tue Sep 08, 2020 6:12 pm

BDanielMayfield wrote: ↑Tue Sep 08, 2020 5:54 pm

There is one caveat to that though: One of the few properties a BH can have is charge. So if two BH where both positively or both negatively charged, there would be an electrostatic force of repulsion working against their gravitational attraction. (Conversely, if the charges where opposite the attraction would be increased.) However, in the real universe it is not likely that BHs will have much charge, so this effect should be negligible.

Bruce

Hmm, I hadn't realized that a black hole could have a charge. And doesn't it also follow that any such charge must be small, because if it was large, the black hole would be blown apart by electrostatic repulsion, since that force is 10⁴⁰ times greater than gravity?

How do you blow a singularity apart? It has no volume.

APOD Robot wrote: ↑Tue Sep 08, 2020 4:09 am GW190521: Unexpected Black Holes Collide

Explanation: How do black holes like this form? The two black holes that spiraled together to produce the gravitational wave event GW190521 were not only the most massive black holes ever seen by LIGO and VIRGO so far, their masses -- 66 and 85 solar masses -- were unprecedented and unexpected. Lower mass black holes, below about 65 solar masses are known to form in supernova explosions. Conversely, higher mass black holes, above about 135 solar masses, are thought to be created by very massive stars imploding after they use up their weight-bearing nuclear-fusion-producing elements. How such intermediate mass black holes came to exist is yet unknown, although one hypothesis holds that they result from consecutive collisions of stars and black holes in dense star clusters. Featured is an illustration of the black holes just before collision, annotated with arrows indicating their spin axes. In the illustration, the spiral waves indicate the production of gravitational radiation, while the surrounding stars highlight the possibility that the merger occurred in a star cluster. Seen last year but emanating from an epoch when the universe was only about half its present age (z ~ 0.8), black hole merger GW190521 is the farthest yet detected, to within measurement errors.

johnnydeep wrote: ↑Tue Sep 08, 2020 6:12 pm

BDanielMayfield wrote: ↑Tue Sep 08, 2020 5:54 pm

BDanielMayfield wrote: ↑Tue Sep 08, 2020 3:54 pm

Black holes, being the chunkiest bodies in the universe, would never be repellent.

There is one caveat to that though: One of the few properties a BH can have is charge. So if two BH where both positively or both negatively charged, there would be an electrostatic force of repulsion working against their gravitational attraction. (Conversely, if the charges where opposite the attraction would be increased.) However, in the real universe it is not likely that BHs will have much charge, so this effect should be negligible.

Bruce

Hmm, I hadn't realized that a black hole could have a charge. And doesn't it also follow that any such charge must be small, because if it was large, the black hole would be blown apart by electrostatic repulsion, since that force is 10⁴⁰ times greater than gravity?

BDanielMayfield wrote: ↑Tue Sep 08, 2020 5:54 pm

BDanielMayfield wrote: ↑Tue Sep 08, 2020 3:54 pm

De58te wrote: ↑Tue Sep 08, 2020 2:57 pm
Just wonder how strong the repelling force would have to be between the two black holes in order to repel a black hole?

Black holes, being the chunkiest bodies in the universe, would never be repellent.

There is one caveat to that though: One of the few properties a BH can have is charge. So if two BH where both positively or both negatively charged, there would be an electrostatic force of repulsion working against their gravitational attraction. (Conversely, if the charges where opposite the attraction would be increased.) However, in the real universe it is not likely that BHs will have much charge, so this effect should be negligible.

• Black Holes do have rotating ergospheres, however.
  
  Dick Caveat around the ergosphere of rotating late night black hole.

BDanielMayfield wrote: ↑Tue Sep 08, 2020 5:54 pm

BDanielMayfield wrote: ↑Tue Sep 08, 2020 3:54 pm

De58te wrote: ↑Tue Sep 08, 2020 2:57 pm Just wonder how strong the repelling force would have to be between the two black holes in order to repel a black hole?

Black holes, being the chunkiest bodies in the universe, would never be repellent.

There is one caveat to that though: One of the few properties a BH can have is charge. So if two BH where both positively or both negatively charged, there would be an electrostatic force of repulsion working against their gravitational attraction. (Conversely, if the charges where opposite the attraction would be increased.) However, in the real universe it is not likely that BHs will have much charge, so this effect should be negligible.

Bruce

BDanielMayfield wrote: ↑Tue Sep 08, 2020 3:54 pm

De58te wrote: ↑Tue Sep 08, 2020 2:57 pm Just wonder how strong the repelling force would have to be between the two black holes in order to repel a black hole?

Black holes, being the chunkiest bodies in the universe, would never be repellent.

De58te wrote: ↑Tue Sep 08, 2020 2:57 pm

orin stepanek wrote: ↑Tue Sep 08, 2020 12:19 pm
Oh My!!! Kaboom! 🌪 If 2 black holes collide; would not that be like 2 strong magnets coming together???? Either banging together or sling themselves fast apart?

Humm interesting. I am no physicist, and maybe a physicist can chime in, but that might have a connection to the Grand Unification theory. I understand that unlike the 3 electromagnetic forces, gravity only attracts. It does not repel. So it is likely that two black holes, which are mainly the forces of gravity, would likely collide, instead of repel. But then there are forces that repel, such as star's solar winds and supernovas. Just wonder how strong the repelling force would have to be between the two black holes in order to repel a black hole?

De58te wrote: ↑Tue Sep 08, 2020 2:57 pm

orin stepanek wrote: ↑Tue Sep 08, 2020 12:19 pm GW190521_Virgo_1080.jpg


Oh My!!! Kaboom! If 2 black holes collide; would not that be like 2 strong magnets coming together???? Either banging together or sling themselves fast apart?

Humm interesting. I am no physicist, and maybe a physicist can chime in, but that might have a connection to the Grand Unification theory. I understand that unlike the 3 electromagnetic forces, gravity only attracts. It does not repel. So it is likely that two black holes, which are mainly the forces of gravity, would likely collide, instead of repel. But then there are forces that repel, such as star's solar winds and supernovas. Just wonder how strong the repelling force would have to be between the two black holes in order to repel a black hole?

Chris Peterson wrote: ↑Tue Sep 08, 2020 3:12 pm

De58te wrote: ↑Tue Sep 08, 2020 2:57 pm

orin stepanek wrote: ↑Tue Sep 08, 2020 12:19 pm GW190521_Virgo_1080.jpg


Oh My!!! Kaboom! 🌪 If 2 black holes collide; would not that be like 2 strong magnets coming together???? Either banging together or sling themselves fast apart?

Humm interesting. I am no physicist, and maybe a physicist can chime in, but that might have a connection to the Grand Unification theory. I understand that unlike the 3 electromagnetic forces, gravity only attracts. It does not repel. So it is likely that two black holes, which are mainly the forces of gravity, would likely collide, instead of repel. But then there are forces that repel, such as star's solar winds and supernovas. Just wonder how strong the repelling force would have to be between the two black holes in order to repel a black hole?

Normally, two bodies like this require no opposing force to keep them separate, because they are in orbit around each other (so, moving under the influence of gravity and of inertia). It's no different from the Earth and Moon- no opposing force keeps us separate. What is different here is that a pair of close black holes radiate gravitational energy, which results in their orbits getting smaller- very quickly so when they're nearly touching. But they are still in orbit- it's not like they're being sucked together by gravity, exactly.

De58te wrote: ↑Tue Sep 08, 2020 2:57 pm

orin stepanek wrote: ↑Tue Sep 08, 2020 12:19 pm GW190521_Virgo_1080.jpg


Oh My!!! Kaboom! 🌪 If 2 black holes collide; would not that be like 2 strong magnets coming together???? Either banging together or sling themselves fast apart? ⁉️ 🤯

Humm interesting. I am no physicist, and maybe a physicist can chime in, but that might have a connection to the Grand Unification theory. I understand that unlike the 3 electromagnetic forces, gravity only attracts. It does not repel. So it is likely that two black holes, which are mainly the forces of gravity, would likely collide, instead of repel. But then there are forces that repel, such as star's solar winds and supernovas. Just wonder how strong the repelling force would have to be between the two black holes in order to repel a black hole?